Alzheimer test developed largely at Penn proves effective

A screening test developed largely at the University of Pennsylvania has proved surprisingly good at predicting who will go from relatively mild memory decline to full-blown Alzheimer's disease.

Scientists are just starting to use this test to identify people at a much earlier stage in the disease and get them into clinical trials of drugs being developed to combat Alzheimer's.

And that's raising hopes that new drugs might fight the disease early, before the brain becomes irreparably damaged, said John Trojanowski, a Penn neuropathologist who helped develop the test - a measure of three proteins in patients' cerebrospinal fluid. Another Penn researcher, Leslie Shaw, also played a lead role in developing the test.

In Trojanowski's vision, doctors may eventually be able to screen for pre-Alzheimer's disease and treat it with drugs the same way they can screen patients for high blood pressure or cholesterol and prevent heart attacks and strokes.

A paper published yesterday in the Archives of Neurology compiled a number of different studies of the test, which requires a lumbar puncture.

The test measures relative concentrations of two key proteins, both of them connected with the abnormal brain deposits that characterize the disease. What separates the positive from negative results is a telltale pattern - an Alzheimer's signature.

One of the more striking results came from a study of 57 people who were initially diagnosed with what's called mild cognitive dementia - a decline in memory and thinking that can be clearly measured by doctors - and then went on to develop Alzheimer's disease within five years.

All of those people had shown an "Alzheimer's signature" on the test before they developed the full-blown disease, Trojanowski said.

Already, Bristol-Myers Squibb is using the screening test to identify subjects for a clinical trial to evaluate the effectiveness of a new drug to treat the disease at a very early stage, said a spokeswoman for the company.

For years, Alzheimer's disease was difficult to distinguish from other types of dementia until the patient died and characteristic brain deposits could be seen on autopsy, said Trojanowski. But when they gave this new screening test to Alzheimer's patients who subsequently died, it proved to be 97 percent accurate in predicting whose diagnosis would be confirmed postmortem.